'Zoomed' CIH

[Pecker]

A while ago we had a video review of the Panasonic PT-AE3000. The projector was noted for having a memory on the zoom so you could switch between 16:9 and 2.35:1 at the flick of a switch, and 'zoom' in for 'scope films instead of using an anamorphic lens.

Questions:

1 - Do any other LCD/D-ILA projectors have this feature?
2 - Do any DLP projectors have this feature?
3 - Can any DLP projectors zoom this much (whether as a memory pre-set, or manually?

Steve W

[KelvinS1965]

1. Not at the moment (watch after CEDIA though)
2. No, as per 1.
3. Hard to find, but try searching through the Projection Calculator putting in potential models. I tried the newer Optoma HD8200 but found it was only x1.27 zoomed which is a little on the low side....there may be others.

BTW, the AE3000 is not 'instant', it has a faffy menu that you have to got through and it displays the message 'processing' during the rezoom/refocus er, process, which isn't as 'slick' as I was expecting when I bought mine. It does seem to be very repeatable though (if you set up the zoom memories when the PJ has warmed up).

Optoma HD8200 Projection Calculator - Throw Distance and Screen Size

[Pecker]

Cheers. Next question.

The JVC 750, I presume it can 'zoom' manually (not a pre-set) enough to do this?

Is the zoom motorized, or do you have to get up and twist the lens?

Ditto the focus.

Steve W

[The Moog]

Pecker,

The HD350 and HD750 both have motorised zoom and focus.


The Moog

[Pecker]

Originally Posted by The Moog

Pecker,

The HD350 and HD750 both have motorised zoom and focus.


The Moog

And have both got enough zoom to go CIH using zoom without an anamorphic lens?

If so, if I wanted the 750 to do this, what's the furthest away I could place it from the screen?

Cheers.

Steve W

[KelvinS1965]

It depends how big your screen is, how far away you want to put the PJ.

If you had a 112" wide 2.35 screen then 19' throw works fine with either the HD350 or HD750 (tried both in my house/screen). I can't go much smaller than 83" wide for the 16:9 (minimum zoom) or bigger than 167" wide for 2.35:1 from 19'. You need to put your figures into the PJ calculator below (already set for HD350, but they're both the same for these purposes).

JVC DLA-HD350 Projection Calculator - Throw Distance and Screen Size

[Pecker]

Originally Posted by KelvinS1965

It depends how big your screen is, how far away you want to put the PJ.

If you had a 112" wide 2.35 screen then 19' throw works fine with either the HD350 or HD750 (tried both in my house/screen). I can't go much smaller than 83" wide for the 16:9 (minimum zoom) or bigger than 167" wide for 2.35:1 from 19'. You need to put your figures into the PJ calculator below (already set for HD350, but they're both the same for these purposes).

JVC DLA-HD350 Projection Calculator - Throw Distance and Screen Size

Sorry, I should have said 3m wide screen for 'scope, smaller for everything else.

Looks like the distance is 4m-8m on that calculator. Do I have that right?

Steve W

[Neil Davidson]

1.78: 1 width = 1.78m
2.35:1 width = 2.35m

Throw ratio = distance of screen to projector lens / width of screen

With JVC HD750 throw = 1.4 to 2.7

thus range of throw distance for "Zoom" method

min = (2.35 x 1.4) / 1.78 = 1.85:1
max = (1.78 x 2.7) / 1.78 = 2.7:1

Remember that you always need to leave some margin for the zoom range not being exactly what is specified. in the above example the real range I would consider to actually install a PJ would be 1.9:1 to 2.65:1.

This was interesting for me as it shows how little difference in the install location there is between the "Zoom" and lens methods. Baically the longer the throw the better in both cases.

Remember these numbers are throw ratios. You can compute the actual distance once you know what size screen you are looking at.

[KelvinS1965]

Originally Posted by Pecker

Sorry, I should have said 3m wide screen for 'scope, smaller for everything else.

Looks like the distance is 4m-8m on that calculator. Do I have that right?

Steve W

EDIT: At 8 metres you won't be able to zoom back enough to fit the 16:9 image on your 3 metre wide screen. You need to be no more than 6 metres for it to work, which is pretty much where mine is with a slightly narrower screen than what you're planing.

[Neil Davidson]

Originally Posted by Pecker

Sorry, I should have said 3m wide screen for 'scope, smaller for everything else.

Looks like the distance is 4m-8m on that calculator. Do I have that right?

I didn't check the calculator to see if it works but the correct range for a 3m scope screen in a zoom config with the HD750 is

4.3 to 5.95m gave or take a couple of cm.

[Pecker]

Cheers.

The figures I put in say the following (please correct me if I've got it wrong).

I'd be going for a 3m wide screen, aspect ratio 2.5:1 (the widest I think I'll need to go).

A 3m wide, 2.5:1 screen is 1.2m tall. So, the 'central' 16:9 area would be 1.2 x 2.13m.

A 3m wide image can be had with the PJ between 4.25m and 8.25m (best 5.49m).

A 2.13m wide image can be had with the PJ between 3m & 5.75m (best 3.88m).

So, if I have this right, the PJ would need to be between 4.25 and 5.75m away, with 'best' being 4.68.5m.

That seems to fit in with your calculations, Neil. Cheers.

Steve W

[Neil Davidson]

Originally Posted by Pecker

(please correct me if I've got it wrong).

OK (sorry couldn't resist)

Originally Posted by Pecker

A 3m wide, 2.5:1 screen is 1.2m tall. So, the 'central' 16:9 area would be 1.2 x 2.13m.

3 x 0.75 = 2.25m wide not 2.13m

or with slightly more accuracy

(3 / 2.35) x 1.78 = 2.273m

If you were zooming you might want to consider 2.4 rather than 2,35 though.

[Pecker]

Originally Posted by Neil Davidson

OK (sorry couldn't resist)



3 x 0.75 = 2.25m wide not 2.13m

or with slightly more accuracy

(3 / 2.35) x 1.78 = 2.273m

If you were zooming you might want to consider 2.4 rather than 2,35 though.

2.5:1 at the widest, Neil. 2.5:1.



Steve W

[Neil Davidson]

Originally Posted by Pecker

2.5:1 at the widest, Neil. 2.5:1.



Steve W

LOL - OK

Somewhat arbitrary choice of aspect though is not? If you are going beyond 2.4 then why not 2.66 or even 2.7?

[Pecker]

Originally Posted by Neil Davidson

LOL - OK

Somewhat arbitrary choice of aspect though is not? If you are going beyond 2.4 then why not 2.66 or even 2.7?

I might be wrong, but I think 2.50:1 is the widest Blu-ray Disc/DVD I've seen, other than the ultra-wide How the West Was Won at 2.89:1.

Don't go there Neil, I'm not doing it!

EDIT: Actually, the widest Blu-ray Disc I have is Sleeping Beauty at 2.55:1. I'll have to re-do me sums. Damn them pesky Disneys!

Steve W